The present disclosure relates to an inkjet head, an inkjet recording apparatus, and a method of producing an inkjet head.
A known inkjet recording apparatus includes an inkjet head that is adapted to discharge ink from a plurality of nozzles. As shown in FIGS. 8 and 9, pressure chambers 143, ink supply channels 131, and ink flow channels 133 are formed in a pressure chamber plate 130 in an inkjet head 110 in the known inkjet recording apparatus. The pressure chamber plate 130 is made from an alumina ceramic or the like. The ink supply channels 131 may supply ink to the pressure chambers 143. The ink flow channels 133 may feed the ink from the pressure chambers 143 to nozzle holes 121 that are formed in a nozzle plate 120. A diaphragm 150 is provided on top of the pressure chamber plate 130. A piezoelectric element unit 160 is provided on top of the diaphragm 150. A pressure may be applied to the ink in the pressure chamber 143 by a piezoelectric element active portion 162 of the piezoelectric element unit 160. The inkjet head 110 also includes a first base member 170, which serves as a spacer, and a second base member 180. The second base member 180 is used in order to fasten the inkjet head 110 to a carriage of the inkjet recording apparatus. In the inkjet head 110, a pressure within the ink is set such that a good ink meniscus is formed at a tip portion of each of the nozzle holes 121. Deformation of the piezoelectric element active portion 162 propagates the pressure that is applied to the ink in the pressure chambers 143, such that a droplet of the ink is discharged from the tip portion of each of the nozzle holes 121.
In a piezoelectric type of inkjet head that discharges the ink by using a piezoelectric element to pressurize the ink in an ink chamber, it is necessary to generate a large pressure within the ink chamber in order to discharge a large droplet of high-viscosity ink. It is therefore necessary to cause the piezoelectric element to generate a large amount of power. Generally, the power that a piezoelectric element generates is large, but the amount of change is small. Therefore, in order to achieve a large amount of change, a layered type of piezoelectric element, like that shown FIGS. 8 and 9, is often used. This means that in a case where the ink chamber has low rigidity, the entire ink chamber may be deformed at times when all of the channels are driven at the same time, and the like. In this sort of case, the required pressure may be not achieved or the discharge of the ink may become unstable. Therefore, in the known inkjet head 110 that is compatible with a high-viscosity ink, alumina ceramic, which is a highly rigid material, may be used for the ink pressure chamber plate 130. Thus the pressure chamber 143 may be formed to have higher rigidity than that formed from an ordinary metal material such as stainless steel or the like.